Function pmaddbw 

fn pmaddbw<'tcx>(
    ecx: &mut MiriInterpCx<'tcx>,
    left: &OpTy<'tcx>,
    right: &OpTy<'tcx>,
    dest: &MPlaceTy<'tcx>,
) -> InterpResult<'tcx, ()>

Multiplies packed 8-bit unsigned integers from left and packed signed 8-bit integers from right into 16-bit signed integers. Then, the saturating sum of the products with indices 2*i and 2*i+1 produces the output at index i.

https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_maddubs_epi16 https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm256_maddubs_epi16 https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm512_maddubs_epi16